Sour/ˈsaʊər/ Definition 1 of 4Pro Tip 1/3Often Negative Sour in taste often implies something is too acidic or maybe spoiled, suggesting a bad experience. The soup has a sour flavor; I can't eat it. Pro Tip 2/3Metaphorical Use Sometimes 'sour' is used metaphorically to describe an experience that left a bad impression. Losing the game left a sour taste in his mouth. Pro Tip 3/3Intensity Sour flavors range from slightly tart to intensely acidic; context helps clarify. Limes are sour, but they're great in small amounts.